Prevalence and risk factors related to infections of cardiac resynchronization therapy devices.

AIMS: Device-related infections (DRI) are not well understood in patients implanted with a cardiac resynchronization therapy (CRT) device. The aims of this study were: (i) to evaluate the prevalence of CRT DRI; (ii) to establish the factors predictive of CRT DRI. METHODS AND RESULTS: Between January 2001 and May 2007, CRT implantation was performed in 303 patients (247 men, 82%). The mean follow-up was 31 +/- 19 months. Population characteristics were a mean age of 70 +/- 10 years old; 56 female; aetiology includes (202 dilated and 101 ischaemic cardiomyopathy); NYHA class 3.2 +/- 0.3; LVEF (26 +/- 6%), and a QRS width of 171 +/- 31 ms. Thirteen patients developed a DRI: endocarditis in four, pocket erosion in three, pocket abscess in five, and septicaemia in one. The prevalence of DRI was 4.3%. By univariate analysis, predictive factors of DRI were: procedure time (skin to skin: median of 85 vs. 57.5 min; P = 0.03), re-intervention (54 vs. 6.5%; P < 0.0001), haematoma (31 vs. 8.6% P = 0.01), lead dislodgement (23 vs. 6.2%; P = 0.03), dialysis (23.1 vs. 1.72%; P = 0.003), and procedure type [CRT-ICD (8.6%) vs. CRT PM (1.6%) or system up-grade (1.5%); P = 0.03]. Significant correlations were found between re-intervention and lead dislodgement (r = 0.8; P < 0.001), haematoma (r = 0.2; P < 0.001). Four independent predictive factors of DRI were identified as procedure time (P = 0.002); dialysis (P = 0.0001); re-intervention (P = 0.006), and procedure type (CRT-ICD vs. other procedures; P = 0.01). CONCLUSION: This study found that the prevalence of CRT DRI is close to 4.3% at 2.6 years (1.7% per year incidence). Four independent predictive factors of infections were identified including re-intervention, procedure time, dialysis, and primo CRT-ICD implantation. These parameters should be part of the risk-benefit evaluation in patients selected for CRT implantation.

Long-term efficacy and safety of radiofrequency ablation in elderly patients with atrioventricular nodal re-entrant tachycardia.

AIMS: The purpose of this study was to evaluate the efficacy, risks, safety, and follow-up of radiofrequency (RF) catheter ablation of atrioventricular nodal re-entrant tachycardia (AVRNT) in patients (pts) > or = 75 years old (n=42) (GpI) compared with pts younger than 75 years (n=234) (GpII). METHODS AND RESULTS: The study population consisted of 276 consecutive pts (39.5% men/60.5% women), from 15 to 98-year-old (average 56+/-17 years) with AVRNT referred for RF ablation (RFA) from October 1997 to January 2004. Combined anatomical and electrogram approaches were used to guide RFA. The cumulative risk of AVRNT recurrence was analysed by the Kaplan-Meier method and log-rank test. The average follow-up was 34+/-18 months. GpI (80+/-4 years) differed significantly from GpII (51+/-14 years) regarding: heart rate tachycardia (160+/-20 vs. 180+/-30 bpm; P=0.0001), the slow pathway antegrade refractory period (370+/-70 vs. 340+/-60 ms; P=0.01), the fast pathway antegrade refractory period (360+/-60 vs. 330+/-60 ms; P=0.003), retrograde refractory period (360+/-60 vs. 330+/-60 ms; P=0.0007), left ventricular ejection fraction (60+/-12 vs. 65+/-7%; P=0.0009), and ischaemic ECG signs during tachycardia (76.2% vs. 61%; P=0.09). RFA was successfully obtained in 275/276 (99.6%), 42/42 in GpI (100%), and 233/234 (99.6%) in GpII. Five complications occurred (1.8%): major complications in two pts (0.7%) and minor complications in three pts (1.1%). Major complications were deep venous thrombosis with pulmonary embolus (n=1) and pericardial effusion (n=1), minor complications were groin haematoma (n=3). One complication was observed in GpI (groin haematoma) (2.4%) and four in GpII (deep venous thrombosis with pulmonary embolus in one, groin haematoma in two, and pericardial effusion in one) (1.7%). The number of recurrences was not statistically different between the two groups (0 vs. 3.4%; P=0.5) with a respective average follow-up of 28+/-18 and 35+/-18 months, respectively. CONCLUSION: Catheter ablation of AVRNT in elderly and very elderly pts appears to be a reasonable approach regarding feasibility and effectiveness without increasing the risk of AV block.

Clinical predictors of cardiac events in patients with isolated syncope and negative electrophysiologic study.

BACKGROUND: Patients with syncope or near syncope of unknown etiology represent a great challenge to cardiologists. An initial symptomatic episode triggers a series of diagnostic analysis which remain unsatisfactory when negative. More invasive tools such as electrophysiologic testing yield only partial answers to risk stratification while the complementary implantable holter diagnostics are not usually considered until a recurrent episode is documented. OBJECTIVE: This study targets predictors of significant cardiac rhythmic events in patients with a reported episode of syncope or near syncope presenting with negative diagnostics and electrophysiologic study results (EPS). A significant cardiac rhythmic event was defined as a combined end-point of (1) symptomatic AV block; (2) symptomatic conduction abnormalities requiring pacemaker therapy; (3) symptomatic sustained ventricular arrhythmia; and (4) sudden death. METHODS: All patients undergoing EPS after a first episode of syncope or presyncope between January 1997 and December 2001 were included for analysis. The study population consisted of 329 pts (42.6% women), 21 to 96 years old (mean 70+/-15 years) referred for an EP study for syncope or near syncope. RESULTS: Of the 329 patients who underwent EPS, 305 (92.7%) had follow-up data. The population, mean age 70 (+/- 15 years) and composed of 42% women, presented with hypertension (51.5%), diabetes mellitus (14.4%), hypercholesterolemia (30%), tobacco use (35%), a familial history of coronary heart disease (22%), history of stroke (4%), history of MI (12%), history of atrial fibrillation (10%), structural heart disease (17.4%), left ventricular ejection fraction 61 (+/- 11%) and ECG abnormalities (37%). These anomalies included right (RBBB) or left (LBBB) bundle branch blocks, left anterior fascicular block (LAFB), left posterior fascicular block (LPFB), bifascicular block (RBBB+LAFB) and traces of myocardial infarction. The mean follow-up was 31+/-20 months with 5% of patients recording significant cardiac rhythmic events (15/305): AV block requiring pacemaker therapy in 7 patients, sinus dysfunction in 4, sudden death in 3 and ventricular tachycardia in 1. Univariate analysis reveals structural heart disease, ECG abnormalities and LVEF associated with the risk of significant cardiac rhythmic events defined by the combined end-point. Multivariate analysis using a Cox model found that the only independent predictor of events was an ECG abnormality. The long-term risk of significant event in the subset with ECG abnormalities is of 10.6% (12/113). If unexplained syncope recurrence was included in the combined end-point, ECG abnormality and LVEF were both determinants with a 13.3% (15/113) risk of a arrhythmic events analysis in the subset of patients presenting with ECG abnormalities and Cox model found ECG abnormality as the only independent predictor of event. CONCLUSIONS: This study demonstrated that an ECG abnormality is the only predictive variable associated with a significant arrhythmic event in patients with a lone episode of syncope or near syncope and a negative EPS.

Simplified cardiac resynchronization implantation technique involving right access and a triple-guide/single introducer approach.

BACKGROUND: Biventricular pacing is useful for patients with congestive heart failure but has the disadvantage of being a long, user-dependent, highly technical procedure. OBJECTIVES: The purpose of this study was to simplify the procedure. The simplified technique consists of sinus (CS) venography prior to implantation, direct coronary access for the left ventricular (LV) lead without use of a left-heart delivery system, and triple-guide/one introducer cephalic vein access as the first approach in patients presenting in sinus rhythm. METHODS: A cephalic cutdown was performed, and a steerable hydrophilic guidewire was introduced in the cephalic vein. A 9Fr introducer was advanced over the guidewire, and two other guides were inserted through the introducer. This technique allowed for insertion of a right ventricular lead, an LV lead, and an atrial lead. RESULTS: One hundred three patients were evaluated from January 2002 to September 2004. Four implants failed (3.9%). The 7Fr LV lead was successfully placed in 99 of 103 patients (96.1%) directly via the 9Fr introducer, without use of a dedicated left-heart delivery system. The final position was lateral in 59 patients, posterolateral in 33, posterior in 4, and anterolateral in 3. Sixty patients were in sinus rhythm, 13 were in atrial fibrillation, and 26 had a previous pacemaker (n = 21) or defibrillator (n = 5). Triple cephalic vein access was possible in 48 of the patients in sinus rhythm (80%). Procedure parameters were as follows: LV threshold 0.9 +/- 0.7 V, LV wave amplitude 15 +/- 8 mV, LV impedance 790 +/- 232 Omega, skin-to-skin procedure time 76 +/- 33 minutes, and fluoroscopy time 23 +/- 19 minutes. Ten complications (10.1%) occurred: 7 lead dislodgments (3 within 48 hours and 4 within 6 months) requiring repositioning (7.1%), 1 subacute local infection requiring explantation (1%), 1 phrenic nerve stimulation (1%), and 1 pneumothorax (1%). The long-term success of biventricular pacing was 93.1%. CONCLUSIONS: This study demonstrates that cardiac resynchronization therapy implantation can be simplified with the combined use of a steerable hydrophilic guidewire, three guides, and one introducer via a right cephalic vein, without use of a left-heart delivery system. The triple cephalic vein approach yields an 80% implant success rate for patients in sinus rhythm. The long-term success of biventricular pacing was 93.1%.

Anatomic and electrophysiological differences between chronic and paroxysmal forms of common atrial flutter and comparison with controls:.

Whether chronic typical atrial flutter differs from paroxysmal atrial flutter regarding electrophysiological properties of reentry pathways and cardiac function remains unknown. If so, can remodeling due to long duration of persistently rapid atrial or ventricular rates explain these changes? The aim of the study was to compare RA local conduction velocities and heart function parameters between three groups: (1) chronic atrial flutter, (2) paroxysmal atrial flutter, and (3) controls. The study evaluated 52 patients undergoing radiofrequency ablation for typical atrial flutter. There were 35 patients with chronic atrial flutter (62.7 +/- 14 years) and 17 patients with paroxysmal atrial flutter (62.7 +/- 10 years). Underlying structural heart disease was present in 20 (57%) of 35 chronic atrial flutter patients and in 7 (41%) of 17 paroxysmal atrial flutter patients (P = 0.1). Chronic atrial flutter duration was 10.9 +/- 17 months and paroxysmal atrial flutter duration was 8.5 +/- 10 (P = 0.06). RA conduction velocity measurements were carried out before ablation during sinus rhythm under pacing (600-ms cycle length) with a 12-pole steerable catheter positioned in the high lateral RA (poles 11-12 [H6]), mid-lateral RA (poles 9-10 [H5]), and along the inferior vena caval tricuspid isthmus (poles 7-8 [H4]; 5-6 [H3]; 3-4 [H2]) with its distal electrode pair at the coronary sinus origin (pole 1-2 [H1]). Counter-clockwise RA conduction velocities were assessed from H6 to H1 and clockwise RA conduction velocities from H1 to H6. After successful ablation, RA and LA areas, LV volumes, LVEF, inferior vena caval tricuspid annulus, and coronary sinus tricuspid annulus (septal isthmus) lengths were measured by two-dimensional echocardiography. The control group included 12 patients without structural heart disease, referred for electrophysiological evaluation of AVN reentry. Counter-clockwise RA conduction velocities at the inferior vena caval tricuspid isthmus were lower in chronic atrial flutter than in paroxysmal atrial flutter (H4, 1.19 +/- 0.4 vs 1.89 +/- 1 m/s, P = 0.0051; H3, 1.14 +/- 0.4 vs 1.6 +/- 0.7 m/s, P = 0.0015; H2, 1.16 +/- 0.4 vs 1.53 +/- 0.5 m/s, P < 0.0056 and H1, 1.2 +/- 0.4 vs 1.5 +/- 0.4 m/s, P = 0.03, respectively). Counter-clockwise RA conduction velocities were identical at the high and mid-lateral RA. Counter-clockwise caval isthmus RA conduction velocities from H3 to H1 were significantly different between chronic atrial flutter and controls (H3, 1.14 +/- 0.4 vs 1.7 +/- 0.3 m/s, P = 0.0014; H2, 1.16 +/- 0.4 vs 1.83 +/- 0.4 m/s, P < 0.0001 and H1, 1.2 +/- 0.4 vs 1.94 +/- 0.4 m/s, P < 0.0001, respectively). A difference was found regarding clockwise isthmus RA conduction velocities between the two groups of atrial flutter and controls but not between chronic atrial flutter and paroxysmal atrial flutter. Respectively, chronic atrial flutter had greater RA and LA areas (24.5 +/- 5 vs 13 +/- 2 cm2; P < 0.0001 and 23 +/- 5 vs 16 +/- 3 cm2, P < 0.0001), LV end-systolic and end-diastolic volumes (50 +/- 25 vs 32 +/- 13 cm3, P = 0.0084 and 112 +/- 40 vs 85 +/- 25 cm3, P = 0.01), septal isthmus length (21 +/- 3 vs 13 +/- 2 mm, P < 0.0001), and inferior vena caval tricuspid isthmus length (39 +/- 6 vs 23 +/- 5 mm; P < 0.0001). Chronic common atrial flutter is characterized by more prolonged counter-clockwise conduction times and larger anatomic conduction pathways than the paroxysmal form, the causal relationship between electrophysiological and anatomic characteristics remains to be demonstrated.

Safety and efficacy of radiofrequency ablation of common atrial flutter in elderly patients: a single center prospective study.

Little data is available concerning the invasive treatment of atrial flutter (AFL) in elderly patients. The purpose of this prospective study was to evaluate the risks, safety, and follow-up of radiofrequency (RF) catheter ablation of common AFL in patients >75 years old (n = 61) (Group I) compared to patients younger than 75 years (n = 187) (Group II). The study population consisted of 248 patients (81% men/19% women), 21 to 96 years old (mean 66.3 +/- 12 years) with AFL, referred for RF from June 1999 to June 2001. RF endpoint was the assessment of the bidirectional block. The cumulative risk of atrial fibrillation (AF) was analyzed by the Kaplan-Meier method and log-rank test. The mean follow-up was 12.4 +/- 9 months. No complication occurred. Group I (80.1 +/- 4.5 years) did not differ significantly from Group II (61 +/- 11 years) regarding: AF history before ablation (34.4% vs 39.8%), structural heart disease (54% vs 42%), LVEF (57%+/- 12% vs 58%+/- 12%), left atrial size (43.8 +/- 7 vs 42.5 +/- 7), cava-tricuspid isthmus dimension (40 +/- 10 vs 39 +/- 4 mm), bidirectional block (100% vs 96.2%), RF application (12.5 +/- 10 vs 13.5 +/- 12 minutes), AFL recurrence (3.3% vs 5.3%), antiarrhythmic agents at hospital discharge (34.4% vs 38.9%), mean follow-up (12 +/- 9 vs 13 +/- 9 months) and AF occurrence (29.5% vs 20.3%; P = 0.2). Of these, the incidence of AF in patients without prior history (n = 150) was 7 (18%) of 39 for Group I and 11 (10%) of 111 for Group II (P = 0.1) after follow-up. Catheter ablation of AFL in very elderly patients appears to be a reasonable approach regarding feasibility, effectiveness, and low procedural risk.